Just a note on apps that display the "Slow Down" warning. This may be meaningless right now but won't be when iOS 11 arrives and all support for 32 bit applications is dropped (i.e. Unless the developer updates, the app is dead).

That's Apple for ya. On the upside I'm reliably informed that this will free up a fair chunk of storage (not having to effectively install two OSs).

As mentioned above, 32-bit complied apps/games will not work in the next major iOS release, so be careful if downloading games containing the warning message fe Apple. Expect to say goodbye to these games under iOS9 unless developers re-compile and update as a 64bit binary. It's not hard to do for most apps but there are many lazy developers out there.